A Genetic Rule-Based Data Clustering Toolkit

Clustering is a hard combinatorial problem and is defined as the unsupervised classification of patterns. The formation of clusters is based on the principle of maximizing the similarity between objects of the same cluster while simultaneously minimizing the similarity between objects belonging to distinct clusters. This paper presents a tool for database clustering using a rule-based genetic algorithm (RBCGA). RBCGA evolves individuals consisting of a fixed set of clustering rules, where each rule includes d non-binary intervals, one for each feature. The investigations attempt to alleviate certain drawbacks related to the classical minimization of square-error criterion by suggesting a flexible fitness function which takes into consideration, cluster asymmetry, density, coverage and homogeny

Improvement of optical resolution in far-field imaging by optical multiplication

Based on the idea of the complex filters suggested by Toraldo di Francia in 1952, super-resolved imaging has been achieved by using interferometric image multiplication. The question of whether super-resolution implies a limited field of view is discussed, and an analytical criterion to decide this question is obtained. Three different imaging configurations are investigated, all of which gave a spatial resolution exceeding that corresponding to the full open aperture of the optical system. A resolution limit 55% of the Rayleigh limit was achieved for incoherently illuminated objects. One price that must be paid for the super-resolution is inefficient use of the light source. A second price is a limitation to the usable field of view

Superresolution in far-field imaging

Based on the idea of the complex filters suggested by Toraldo di Francia in 1952 [Nuovo Cimento Suppl. 9, 426 (1952)], superresolved imaging has been achieved by use of interferometric image multiplication. A resolution limit of 55% of the Sparrow limit was achieved for incoherent objects

Organizational culture and resistance to change in the chania general hospital. Upgrade of service quality

OBJECTIVE Assessment of the possibility of applying a new model of management (Total Quality Management) in the General Hospital of Chania in Crete, aimed at upgrading service quality. METHOD The present organizational culture in the hospital was investigated, along with the wishes for the next five years of the hospital personnel, and the level of resistance to change among the personnel was assessed. The study participants were 160 hospital employees selected by the method of non-random sampling, based on quota per service category (doctors, medical personnel other than doctors, nursing personnel, administrative and technical service personnel and other scientific specialties). The Organizational Culture Assessment Instrument (OCAI) and the Resistance to Change (RTC Scale) were completed by the participants for the measurement of organizational culture and resistance to change, respectively. RESULTS The current dominant culture that emerged from the responses to the OCAI is the hierarchical, which is based on control (32.49%), and the desirable culture reported for the next five years is the clan culture, which is based on cooperation (32.67%). The cultures with the lowest recorded rates were, for the present, the adhocracy culture, which is based on creation (18.69%), and for the next five years the market culture, which is based on competition (18.73%). Concerning attitudes towards change, the scores showed marginally average values for total resistance to change (3.01 on a scale from 1 to 6), with slightly higher scores on the subscale of cognitive rigidity (3.75), expressing the cognitive processing of change. Non-parametric tests, applied to detect possible variation in scores according to the demographic characteristics of the sample, showed no statistically significant differences (p<0.05). Spearman correlations showed no relationships between cultures and resistance to change, with the exception of correlation between the current adhocracy culture and cognitive rigidity (p=0.00) and between the current hierarchical culture and total resistance (p=0.002). CONCLUSIONS Success in implementing the Total Quality Management model presupposes the coexistence of elements of all cultures in an organization. The presence of elements of all cultures in the General Hospital of Chania (indicating the absence of one strong culture) and the mean values in resistance to change, are positive aspects for the application of such a model in this hospital. © Athens Medical Society

The impact of socio-demographic features on anxiety and depression amongst navy veterans after retirement: A cross-sectional study

Objective: Retirement from work may trigger various changes in everyday life that affect mental health. The current cross-sectional study, conducted with 231 veterans, examines the relationship between socio-demographic features and both anxiety and depression in navy veterans after retirement. Spielberg's State-Trait Anxiety Inventory (STAI) was used for anxiety assessment, and the Beck Depression Inventory (BDI) was used for depression assessment. The analysis was performed with the Statistical Package for Social Sciences (SPSS), version 20.0. Results: It was found that the mean score of state anxiety was 41 and trait anxiety, 38. Severe depression was found in 6.5% of the veterans, moderate in 8.3% and mild in 21.7%. The presence of a serious health problems was an independent predictor of both anxiety and depression's more serious symptoms. Inversely, the stability in terms of retirement choice was negatively related to depression, while the development of new interests and activities after retirement was negatively related to both anxiety and depression. Further, life satisfaction after retirement was a predictor of lower current anxiety levels among veterans. © 2020 The Author(s)